This invention relates to a multiprojection system using plural projectors, in which the arrangement and size of images can be freely changed and each image can be freely flown, and particularly to a multiprojection system which enables changeful representation as a new screen image system in which a screen image is harmonized with lighting in a representation space.
In a conventional multiprojection system, as shown in FIGS. 7(a) and 7(b), projection planes of plural projectors are closely contacted with each other so that the projection planes can be regarded as one large image plane, which is called a projection cube system, a multivision system, videowalls or the like.
In one example of the multiprojection system, as shown in FIG. 7(a), 12 projector units 96 each having an image plane size of 600 mm (length).times.800 mm (width) are superposed so that three projector units 96 are arranged in lines longitudinally and four projector units 96 are arranged in lines laterally. By such superposing, entire image planes form a large image plane having a size of 1,800 mm (length).times.3,200 mm (width).
As shown in FIG. 7(b), a projector 97 is provided in each projector unit 96. There is a screen 98 in front of each projector 97, and an image is projected from the inside by the projector 97.
In these systems, there are some systems in which joints of overlapped portions (including unevenness of luminance) cannot be completely prevented. However, irrespective of this disadvantage, these systems have frequently been used for the following reasons.
That is, most of projectors used in this kind of system are liquid crystal projectors or three tube type projectors using the RGB calorimetric system, or television monitors (CRT) themselves are used. However, in generally used projectors, brightness is limited under the present technology. When an image is enlarged on the above large image plane having a size of 1,800 mm (length).times.3,200 mm (width) by one projector, it is difficult to ensure the brightness of the large image plane, so that a screen image cannot be seen clearly when a surrounding space is not made dark.
Therefore, it is attempted to obtain an entirely bright large image plane by making the area of one image plane smaller to ensure each brightness and arranging a large number of small image planes in lines. As a matter of course, this system is not limited to the above system using 12 projectors, and by arranging more than 12 projectors in lines longitudinally and laterally, a larger bright image plane can be constituted.
When a large-sized projection system is used, a large image plane can be obtained by one projector. However, the large-sized projection system is extremely expensive and is not convenient for a representation space which should be moved.
The interesting point of the above system resides in that, for example, as shown in FIG. 7(a), the same image or different images can be projected by each of the above twelve projectors, or one image can be projected by assigning divided images to all or some of the twelve projectors and arranging and compositing the divided images, so that representation of changeful and various combinations can be provided as compared with a system in which an image is projected on a large image plane only by one projector.
Therefore, these systems have frequently been used for a representation space since not only images for presentation in a conference hall and explanation in an exhibition hall can be provided, but also impressive and changeful representation can be made by a large image plane.
However, these systems have, in addition to the above problem that joints cannot be completely prevented, a disadvantage that a representation effect is limited since the size and position of an image of each projector are fixed or since the image of the projector is merely a flat image.
On the other hand, as one means for heightening a representation effect, which is different from a multiprojection system, a technique of moving an image to make representation changeful has been developed. For example, there may be mentioned a technique of arranging a rotating mirror immediately in front of a projection lens of an image to change the projection direction of the image. At the time of projection, if the image is moved merely by rotation of one mirror, there is a drawback that the image is inclined in a reverse direction by the angle of a pan angle of the mirror. Therefore, in order to always move the image in a horizontal state, it is necessary to further use a technique of preventing or correcting inclination of the image.
As a method for projecting an image, in which this disad vantageous inclination of an image is prevented, there has been published, for example, "IMAGE MOVER" disclosed in U.S. Pat. No. 5,365,288. According to the above U.S. patent, "a K mirror in which mirrors are arranged in a K-shaped state" or "a dope prism" is arranged near to an image device of a rotating projection mirror, and the K mirror is rotated in a reverse direction by an angle of 1/2 of the pan angle of the projection mirror, whereby inclination of a projected image is prevented.
A problem in the method of the above U.S. patent is that five reflecting planes including the K mirror are given in the example of the above U.S. patent, so that when the reflection efficiencies of the respective mirrors are multiplied, loss of about 50% of light brightness is caused. That is, when this method is employed in the system of the present invention, brightness is reduced by half to cause a result which is contrary to one object of a multiprojection system, i.e., "a multiprojection system is used in order to ensure brightness".
This method is mechanically complicated and requires a large-sized apparatus, makes it difficult to introduce a multiprojection system and results in extremely expensive installation. The object of the above U.S. patent is only to move an image singly, and in the above U.S. patent, there is not any concept regarding the multiprojection system of the present invention.
In the screen image market, particularly in a representation space, further changeful representation has been desired accompanied with diversification of representation. That is, in a representation space, an image for presentation to be used as supplement of explanation in a large conference hall or an image merely like an enlarged telescreen is insufficient, and not only an impressive large image plane is required, but also further changeful and artistic representation should be made.
Further, in a representation space, lighting has an important meaning. In the prior art, a screen image and lighting have been considered to be separate from each other and planned and made by different producers. However, in a future representation space, it is an important task to provide new representation by harmonization a screen image with lighting. For example, among lighting equipments, there are a moving light and a mirror scan. In such light equipments, a starting sheet or a color foil having a pattern which is called GOBO is provided, and the above pattern can be projected as light while the color of the pattern is changed.
Since its light can be freely moved, a changeful and dynamic representation effect can be obtained as compared with simple lighting, so that the MOVING LIGHT and the MIRROR SCAN have frequently been used in a representation space.
These moving light and mirror scan can be regarded as one step of harmonization of a screen image with lighting. However, in a future new representation space, it is an important task to heighten the level of such a simple pattern and introduce a screen image which enables more complicated and effective representation into the field of lighting.
In relation to the foregoing, an image control system and a lighting control system have completely been separated in the prior art. Since the interface of signal systems becomes complicated even in one representation, a long preparation time is required. In order to solve such a problem, it is also an important task to enable easy preparation by harmonization of a screen image with lighting.
Further, as a precondition to a method for achieving the above tasks, it is required to supply an inexpensive and simple system and to provide a system satisfying a requirement that joints and uneveness of luminance of each screen image be made as inconspicuous as possible.